Assignment:
Below is a sequence of DNA near the start of a gene. Use it (and the attached codon table, or an online codon table) to answer the following questions. (Note: correctly indicating the 3' and 5' ends of DNA and RNA molecules is extra credit!)
1. Is this the template strand or the coding strand?
2. What is the complementary strand sequence? (Write it on the line below)
3. Using the template strand of the DNA, what is the mRNA sequence? (Assume that none of the bases are spliced out of this sequence. Remember that the template strand is complementary to the mRNA.)Find and circle the start codon in your sequence.
4. Rewrite the mRNA codons only on the lines below. Put each codon sequence on a separate line (you may not need all the lines provided). Be sure to begin with the FIRST start codon in the sequence.
5. What are the complementary anticodons on the tRNA molecules? (write "STOP" for stop codons, and do not write any anticodon sequences after a STOP codon)
6. What is the amino acid sequence that corresponds to the mRNA sequence above?
7. How many amino acids are coded by this mRNA molecule?
8. Assume that a mutation occurs at position 17 (underlined above) of this DNA sequence, turning the A to a G.
a. What is the new mRNA sequence?
b. What is the new codon sequence? Find and circle the FIRST start codon in your sequence. Put each codon on a separate line (you may not need all the lines provided).
c. What are the new tRNA anticodon sequences? (write "STOP" for stop codons, and do not write any anticodon sequences after a STOP codon)
d. What is the new amino acid sequence?
e. How many amino acids are coded by this mRNA molecule?
